<template>
<view>
  <my-search h @click="gotoSearch"></my-search>
  <view class="scroll-view-container">
    <!-- 左侧的滚动视图区域 -->
    <scroll-view class="left-scroll-view" scroll-y :style="{height: wh
    + 'px'}">
      <block v-for="(item, i) in cateList" :key="i">
        <view :class="['left-scroll-view-item', i === active ? 'active' : '']" @click="activeChanged(i)">
        {{item.cat_name}}
        </view>
      </block>
    </scroll-view>
    <!-- 右侧的滚动视图区域 -->
    <scroll-view class="right-scroll-view" scroll-y :style="{height: wh
    + 'px'}" :scroll-top="scrollTop">
      <view class="cate-lv2" v-for="(item2, i2) in cateLevel2" :key="i2">
        <view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
        <!-- 动态渲染三级分类的列表数据 -->
        <view class="cate-lv3-list">
          <!-- 三级分类 Item 项 -->
          <view class="cate-lv3-item" v-for="(item3, i3) in item2.children"
          :key="i3"  @click="gotoGoodsList(item3)">
            <!-- 图片 -->
            <image :src="item3.cat_icon"></image>
            <!-- 文本 -->
            <text>{{item3.cat_name}}</text>
          </view>
        </view>
      </view>
    </scroll-view>
  </view>
</view>
</template>

<script>
  export default {
    data() {
      return {
        wh: 0,
        active: 0,
        scrollTop: 0,
        cateList: [],
        cateLevel2: []
      }
    },
    onLoad() {
      // 获取当前系统的信息
      const sysInfo = uni.getSystemInfoSync()
      // 为 wh 窗口可用高度动态赋值
      this.wh = sysInfo.windowHeight-50
      this.getCateList()
    },
    methods: {
      async getCateList() {
        // 发起请求
        const { data: res } = await
        uni.$http.get('/api/public/v1/categories')
        // 判断是否获取失败
        if (res.meta.status !== 200) return uni.$showMsg()
        // 转存数据
        this.cateList = res.message
        this.cateLevel2 = res.message[0].children
      },
      activeChanged(i) {
        this.active = i
        this.cateLevel2 = this.cateList[i].children
        this.scrollTop = this.scrollTop === 0 ? 1 : 0
      },
      // 点击三级分类项跳转到商品列表页面
      gotoGoodsList(item3) {
        uni.navigateTo({
          url: '/subpkg/goods_list/goods_list?cid=' + item3.cat_id
        })
      },
      gotoSearch() {
        uni.navigateTo({
          url: '/subpkg/search/search'
        })
      }
    }
}
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;
      .left-scroll-view {
        width: 120px;
        .left-scroll-view-item {
          line-height: 60px;
          background-color: #f7f7f7;
          text-align: center;
          font-size: 12px;
          // 激活项的样式
          &.active {
            background-color: #ffffff;
            position: relative;
            // 渲染激活项左侧的红色指示边线
          &::before {
            content: ' ';
            display: block;
            width: 3px;
            height: 30px;
            background-color: #c00000;
            position: absolute;
            left: 0;
            top: 50%;
            transform: translateY(-50%);
          }
        }
      }
    }
  }
.cate-lv2-title {
  font-size: 12px;
  font-weight: bold;
  text-align: center;
  padding: 15px 0;
}.cate-lv3-list {
  display: flex;
  flex-wrap: wrap;
  .cate-lv3-item {
    width: 33.33%;
    margin-bottom: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
    image {
      width: 60px;
      height: 60px;
    }
    text {
      font-size: 12px;
    }
  }
}
</style>
